about the suspects, and if the f-b-i did enough before the bombings. in 2011, the f-b-i says it interviewed the older brother, tamerlan, after russian authorities alerted the u-s government. he then made a six-month trip to russia in 2012,but his exact whereabouts and activites are unclear. >> "the ball was dropped in one of two ways, the fbi missed a lot of things is one potential answer, or our laws do not allow the fbi to follow-up in a sound, solid way." >> reporter: while officials sift through the details, worshippers sought answers in their own way-- gathering at the cathedral of the holy cross sunday to reflect on the violent flare their city experienced in the last week. moving forward, governor deval patrick says there can be vigilance without fear. >> "there are some lessons we're going to have to learn and have learned painfully through this last experience that will have to be applied to future marathons, but there will be future marathons and i think they'll be bigger and better than ever." >> reporter: govorner patrick is asking resident